Incremental development workflow

In my setup: when using `make test-ghci` module reloading (`:r`) doesn't necessarily reload the source files under the `/src` directory. It seems like it only considers the `/test` directory as interpreted. So if I change a code in `src/Course/Functor.hs` and run `:r` in the test ghci session, it doesn't reload the newly modified `Functor.hs` file.

However, running the following command works as expected.
```
$ stack exec ghci -- -isrc -itest test/Spec.hs
λ: :main --match=Course.Functor/
λ: -- modify src/Course/Functor.hs
λ: :r
λ: :main --match=Course.Functor/
```

Start with the `make test-ghci` workflow and compare it with the working `stack exec ghci -- -isrc -itest test/Spec.hs` command. Use `src/Course/Functor.hs` and `test/Spec.hs` to reproduce the reload behavior; done means editing the source file and running `:r` in the test GHCi session reloads it correctly.

Written by the indexing model from the issue text.